Tillage Farm Management Notes: 16/03/2010
Keep Spring barley seeding rates high
Michael Hennessy
At this time of year crop growth should be gathering steam and grass should be waving in fields all over the country. However crops have not moved over the past week and fertiliser applied over the past week is still sitting on the surface of the ground. Increased temperatures and rain are forecast over the next few days which will help fertiliser to penetrate the soil for uptake by the plants.
Good progress has been made over the past week with sow gathering pace. The good drying weather over the past few days has allowed growers with lighter land to achieve good seedbeds. Achieving a good seedbed in heavier land has been trickier. Soil underneath the surface is still sticky and most growers are rightly leaving this ground for a little while to dry further.
Whether its worthwhile or not to plant spring barley this year is up to each individual grower to work out his own costs. The choice of spring barley varieties this year is similar to last year. Centurion has been dropped off the Department Recommended list and Cropton has been added. Of the varieties on the list most people are very familiar with Frontier, Cocktail and Quench. These varieties have proved themselves over the past three to four years. Frontier has the weakest straw and is the weakest on disease resistance. Quench has preformed well over the past couple of years and is generally a very good all rounder with reasonable straw (but can brackle) and one of the best on the list for disease resistance. Snakebite is a newer variety and is fully recommended. It preformed reasonably well last year and stood well in comparison to other varieties. Of the provisional recommended varieties Magaly was the most widely grown last year and grower experience has been mixed. Its standing power has come into question with straw breakdown cited as its biggest failing. To be fair conditions last harvest didn’t help and in a normal year this variety may stand up quite well but would benefit from prompt harvesting in any year. Cropton is a new variety to the list and preformed well up to last year. Its yield dropped a little last year but its overall three year average yield still compares well. Its standing power is ok and it is prone to straw breakdown. Again it’s a variety where prompt harvesting should be strongly considered. The variety has a good disease resistance profile and is similar to Quench.
Seeding rates for spring barley will depend on a number of factors. Native seed saved this year is not as plentiful as a normal year. Its hard to expect any different considering the harvest last year. Many growers may be using imported seed this year. A minimum germination of 85% is required for the sale of certified seed in Ireland. In some cases native seed will exceed this figure. However as information is not available on individual seed lots it is best to assume germination rates will be closer to 85% than 98%.
Soils are running 2 degrees C lower than normal and therefore additional losses of seed can be expected when planting into these cold seed beds. From this starting point we also need to have an eye on the finishing line. One might say a target yield of three tonne per acre is a lofty challenge but in order to generate any profit this is where we need to aim. To generate this type of yield, a field needs (per meter squared) 280 plants, producing an average of three ears per plant with 19 grains per ear, with a thousand grain weight of 45.7 grams. With these parameters fulfilled, on average through the field, a target yield of three tonnes per acre will be fulfilled.
So the first building block is an established plant stand of 280 plants per meter squared. Allowing for a seed loss of 15% then the target seeding rate to achieve this is between 177 -193 kg/ha (11.3-12.3 st/ac) for spring barleys this year. These seeding rates can be reduced if seed beds are excellent but keep in mind that soils are colder than normal this year.
